Ceiling fan exhaust and toilet venting

I recently had a new bathroom installed in a basement. In order to reduce the number of holes placed in the exterior of the house, the contractor joined the toilet vent pipe to the same exhaust pipe as the ceiling fan exhaust. Is this arrangement acceptable? I'm certain that odors are now coming down through the ceiling fan when it is not exhausting.

I think your nose has answered the question for you.

The contractor joined the waste vent pipe to the bathroom's exhaust fan duct? I'd love to see a picture of that set up.

No. It's neither acceptable or built to code. Were any permits pulled to do this work?

Dan

I can't believe your contractor did that. If he made THAT mistake, I shudder to think what other things he believes are acceptable building/elec/plumbing practices.

The waste vent system vents (toxic) sewer gasses to the roof - where no humans can smell them readily, and provides air to the drain pipes so water can flow and traps are protected.

The bathroom exhaust fan's main purpose is to remove moisture from the air.

Bath exhaust ducts are typically larger diameter (4" + ) than the plumbing vent (3" -)

A fan at one end of a vent pipe too small for it is just asking to blow out a trap. And sewer gasses will fill yr bathroom.

I don't think the (plumbing) vent exhausts any toxic or noxious gases above the roof..But a lack of said vent would indeed suck a trap dry and invite same gases into the living spaces.

Lancaster said:

I don't think the (plumbing) vent exhausts any toxic or noxious gases above the roof..But a lack of said vent would indeed suck a trap dry and invite same gases into the living spaces.

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Sewer gas is methane, and methane can be lethal, and is also explosive (learned this from a septic tank contractor years ago). A vent is open straight to the sewer line, or septic tank, so whatever vapors the septic tank or sewer line are giving off will exit the vent line under certain circumstances, and with the bathroom fan on the same line as the vent, I could only imagine this!!!

Lancaster said:

I don't think the (plumbing) vent exhausts any toxic or noxious gases above the roof..But a lack of said vent would indeed suck a trap dry and invite same gases into the living spaces.

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Go up on your roof and take a whiff at the vents now and then. They're not always toxic or noxious, but they're occasionally pretty nasty. As Verdeboy commented, your nose has already told you this is a bad idea.

Lancaster said:

I don't think the (plumbing) vent exhausts any toxic or noxious gases above the roof..But a lack of said vent would indeed suck a trap dry and invite same gases into the living spaces.

Click to expand...

I guess yr right - the plumbing vent doesn't exhaust sewer gasses per se, but it does provide an entry point for air for drainage, which implies that it will coincidentally provide an exhaust path for sewer gasses. If that's gonna happen, it needs to be where people aren't gonna sniff/ignite em.